The country's most senior Liberal Democrats warn that a strong performance by
Eurosceptic Ukip in next year's European election will harm the UK's
economic recovery.

Voting for the UK Independence Party will derail Britain’s economic recovery, the Government’s two most senior Liberal Democrats warn today.

Nick Clegg and Danny Alexander signal that continued growth will be “jeopardised” by a strong result for Ukip vote in next year’s European Parliament elections.

In his New Year message Mr Clegg, the Deputy Prime Minister, warns that a vote for a party that wants to leave the European Union is “the surest way to throw our recovery away”.

And in an article for The Daily Telegraph Mr Alexander, the Chief Secretary to the Treasury, suggests that a “surge” in anti-European sentiment as a result of a strong showing in the polls by Ukip would lead to less investment in the UK.

A significant vote for Nigel Farage’s Eurosceptic party will “send a shiver of doubt” through corporations with British interests, Mr Alexander says.

He also says that the Conservatives and the Liberal Democrats must keep the Coalition together until 2015 to keep the economic recovery on track

Ministers will “drive the Coalition forward to the very end of the parliament” because it is the only way to ensure growth for the UK, Mr Alexander adds.

Mr Clegg and Mr Alexander are members of the Government’s “quad”, alongside David Cameron and George Osborne.

The four men meet informally and effectively to run the Coalition government.

Ukip is expected to outperform both the Conservatives and the Lib Dems in next May’s elections.

Mr Clegg also uses his New Year address to attack the Conservatives and Labour over their positions on Europe.

“In May you are going to choose who represents you in the European Union,” Mr Clegg says. “Two of the parties on offer could help lead Britain out of Europe, the surest way to throw our recovery away. And the other one won’t lift a finger to help us stay in.

“Ukip want out. The Conservatives are flirting with exit. And Labour just don’t have the courage of their convictions on this. All three would put narrow political interests ahead of the national economic interest.”

Describing the Lib Dems as “Britain’s party of In”, Mr Clegg adds: “Once Britain finds itself with one foot out the door we won’t just be able to turn back. So don’t take that risk. Don’t let anyone jeopardise our recovery.”

Mr Alexander warns that Britain’s recovery could be hampered if Ukip has a strong showing in May’s European elections.

“Weak demand from the Eurozone is still a problem, but our place in Europe is one of the reasons Britain is seen as a great place to invest,” he says.

“A surge in anti-European sentiment in the Euro elections would send a shiver of doubt into the boardrooms of global companies that see a Britain in the EU as a gateway to the single market.”

Mr Alexander also says that if Scotland was to become independent after next year’s referendum it would “undermine” the economic certainty that secures business investment.

Mr Alexander’s comments on the need for the Coalition to last two more years come amid growing disagreements between the Tories and the Lib Dems over issues including immigration and Europe.

Vince Cable, the Business Secretary, outraged Tory Cabinet colleagues earlier this month by comparing David Cameron’s rhetoric on immigration to Enoch Powell’s “rivers of blood” speech.

Mr Clegg has also repeatedly attacked Conservative plans to further toughen up restrictions on European Union migrants coming to the UK.

He has described Tory proposals to cap EU migrants at 75,000 a year as “illegal and undeliverable”.

In his article, Mr Alexander hails the Government’s efforts to increase growth and says that the economy will improve further “every day the Coalition continues its work”.

“The Liberal Democrat promise to the British people for 2014 is that we will stick to our plans to make sure this is a recovery that is built to last,” Mr Alexander says.

“That is the only way to improve living standards. That is why we will continue to drive the Coalition forward to the very end of the parliament.”

George Osborne, the Chancellor, used his Autumn Statement earlier this month to unveil more optimistic forecasts for economic growth and the deficit

The Centre for Economic and Business Research has also forecast that Britain is on track to overtake France and Germany to become the biggest economy in Europe.

In an upbeat assessment of the country’s prospects, the CEBR said Britain, the sixth biggest economy in the world, will see its GDP grow from £1.59 trillion to £2.64 trillion by 2028.

In the same period, Germany’s output will grow more slowly from £2.2 trillion to £2.69 trillion, with growth hampered by a weak euro, an ageing population and the prospect of future Eurozone bailouts. It puts Britain on course to surpass Germany by 2030.